RFR: 8341784: Refactor TypeVect to use a BasicType instead of a const Type* [v3]

[Quan Anh Mai]

> Hi,
> 
> This patch refactors `TypeVect` to use a `BasicType` instead of a `const Type*` as our current implementation. This conveys the element information in a clearer and safer manner.
> 
> Please take a look and leave your reviews,
> Thanks a lot.

Quan Anh Mai has updated the pull request incrementally with one additional commit since the last revision:

  more style changes

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Changes:
  - all: https://git.openjdk.org/jdk/pull/21414/files
  - new: https://git.openjdk.org/jdk/pull/21414/files/90f11d40..a99a7434

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=21414&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=21414&range=01-02

  Stats: 11 lines in 3 files changed: 0 ins; 0 del; 11 mod
  Patch: https://git.openjdk.org/jdk/pull/21414.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21414/head:pull/21414

PR: https://git.openjdk.org/jdk/pull/21414